VOLUME XXI,  NUMBER 11 - NOVEMBER,  2019

Tech Stuff

Project LS-10, Part 3

Roll cage: we are learning as we go forward.

We got the roll cage finished, and here’s how we did it.

 

Well, as the saying goes, “all good plans are subject to change.” The truck itself is coming along great as you will see in this month’s article, but as I look further down the road towards the engine…ideas are changing. I will leave it there for now, but our goal is the same. We want a winning combination for S/Pro (Box), PRO (No Box) and Sportsman (Footbrake) races.

 

Let’s start off with where I left you last month. The S&W rear frame kit was installed, and all the 4-link suspension assembled and most of the body prep was complete. This month we will go over the rear third member choice, axles, a peak at the awesome BAER Brakes we chose and the ideas we used to get the roll cage installed.

 

We received the Quick Performance third-member and the 35-spline race axles about five days after we ordered them. I talked to Aaron at Quick Performance and he provided easy instructions to get the correct information back to him to make sure the axles were a perfect fit. We are going to use the Yukon brand aluminum 9” Ford third member, 4.56:1 Pro-Gear with billet front pinion support, and a billet yoke made for 1350 U-joints.

As you can see -- and this is a new feature to me -- the ring gear has “double bolts” attaching it to the spool. I would guess this is to reduce gear deflection and add longevity the ring and pinion. The instructions say to use non-synthetic 80-90 “GL5” gear lube during break-in. I will be using Schaeffer’s Oil products. I am sure we will switch to synthetic after following the break-in procedures for the ring and pinion.

I wanted to get the correct ride height so I made a cheap (like $2.00) struts drilled for 13.5" to simulate the rear coil-overs. Just wanted to make sure everything fit and cleared and this allowed us to finish the anti-roll bar fabrication work.

Main roll cage rear hoop. Take your time and get the height correct. A larger hole where it goes through floor will help.

 

Once we had the roll bar tubing all cleaned up of the protective oils they have on them for shipping and storage, time to figure out how to get them fit and tack-welded together. First up was to figure out how to use the “outrigger support tubes” that S&W sent and get them attached to the truck’s OEM frame. We measured the width of the roll bar and I cut some 8”x8” square holes through the floor. The outriggers need to run from the truck’s frame out towards the rocker panel so the main hoop of the roll bar would be welded to the frame and not to a plate welded to the truck floor. We feel this is the stronger choice and that is why S&W sends the pre-cut pieces. It is worth the extra effort and adds to the safety the roll cage will provide.

My son Andy came up with the idea of using the 2”x4” outrigger tubes but cutting the front ones at an angle just so they wouldn’t be visible below the rocker panel. You can see the angle he used on the front outriggers. Took about 20 minutes and added a nice finishing touch.

 

We had to trim a few inches off the main tube once we had the outriggers tack-welded in place. NOTE: Go slow, measure three times and then cut the pipe. I always err on the long side so after a few cuts of about ¼” at a time we got the height we wanted. We tacked that bar in. Next up was the “roof halo” that runs from both sides of the main roll bar forward and then across the front behind the windshield opening. This piece requires a “tubing notcher” to let us fit the pipes together and for us rookies a little extra thought. We used a very simple tubing notcher that clamps in our shop vice that I had purchased about 20 years ago. Pretty sure it was called the “ol Joint Jigger” or something like that. I am sure Summit or Jegs has them for about $100. It has a shaft you hook a hole-saw cutter blade to. We used the 1-5/8” Milwaukee hole-saw and then use a ½” drill attached to the top of the shaft.

 

Worked like a champ and after a few practice cuts on scrap pieces, to see how we needed to allow for measuring, we notched the first piece of the S&W Race Cars kit. Worked great and of course my first cuts were too long. Better safe than sorry, right? That’s fine, trimmed them again and a little finish grinding to get the fit as good as I could and we tack-welded them in a couple spots to hold them in place.

This was the "garage fix" to holding the halo-bar in place so we could get the correct height and measurement for the windshield pillar support bar.

Windshield pillar support bar tack-welded in place.

This is the view from above the floor showing windshield pillar bar tack welded to the frame outrigger tubing.

Main (rear) roll bar tubing tied into the frame outrigger support tubing.

 

The “roof halo bar” ended up fitting exactly how we wanted it to, but the tack welds were not strong enough to hold it in place and we did not want to put more weld on it yet. We took a motorcycle ratchet tie-down and ran it through the door openings and over the roof (use some towels to protect paint or primer in our case). It supported the bar and allowed us to start on the windshield pillar bars that would run from the halo bar down to the frame outrigger along the cowl and front hinge pillar. You have a choice when you order the kit from S&W to get the “thru-the-dash” or the “around-the-dash” bar. We chose the straighter “thru-the-dash” as we planned to make our own lightweight dash.

 

This bar was a bit more challenging for us as it has a bit of a “roll” to it as it leaves the halo bar on top and gets vertical when it hits the frame outrigger. My suggestion is to get the top to fit first, have the hole in floor big enough to get pipe next to the outrigger. This makes getting the correct length easier.

 

The rear seat support bar was a pretty easy piece to fit. Of course it helped that we were figuring out how much to allow for the notch in the tubing. The front dash bar was simply a straight piece notched on both ends. NOTE: One consideration on the dash bar though. If you are using your stock steering column, put the column in to make sure you have clearance or if you are going to use a tubular steering column kit make sure you have the kit and the special rod-end for the shaft so you can trial fit the height you want on the column.

We jacked up the cab to give us full access to the tops of the roll cage tubing to complete the welds.

Raising the cab provides better access.

 

Everything was tack-welded in place and now it was time for the “welder in the family”, my son Andy to finish welding the roll cage. If you have ever done this before you know it is “more than difficult” to reach the top of the roll cage to weld the tubing completely, especially true if you have a uni-body car.

This is the finished welding on the front outrigger and the windshield support tubing.

Raising the cab let Andy "do his thing" without little Millermatic MIG welder.

 

We simply took the cab mounts off and used a floor jack on each side and a bunch of 2x4s to raise the cab straight up about 10 inches. That allowed us wide open access to the roll bar tubes and welding 100% around the bars was not an issue. Our shop is like a lot of our readers’ shops. We do not have a big powerful welder, but it is a pretty nice Millermatic and with .035” wire and the right gas mix added to Andy’s experience in welding I am 110% sure this will be the safest and nicest door car I have ever owned.

Rear seat support/shoulder harness mounting bar in place. TECH TIP: Get your seat height determined (we used 2x4s and plywood, so you know where to locate this important piece of roll cage tubing. Two inches below your shoulder height is the recommended height. Too low and it can compress your spine in a crash and too high it will not limit forward travel correctly.

This shows the windshield pillar support bar going through the floor to the outrigger and the junction of the side bar and the optional "rocker bar" we installed.

We decided to install a "rocker bar" to add additional protection for the driver in the event of a side impact. We used the two "front frame support tubes" to build these. I liked the curve they had that allowed the rocker bar to stay along the rocker then turn in to the main roll cage. If we decide we need the front frame supports we will order from S&W and weld them in.

This is where we put the side bar. We wanted it located in line with the rear support bar. It runs between our shoulder and elbow for best protection.

This shows the dash bar installed with the steering column in place to assure proper clearance. Also shows the "trick 2x4 wood" temporary seat mounts.

Finished roll cage painted and ready in case we need it.

 

Next month I will show you how we got our first aluminum dash built and the wheel tubs installed. I know a lot of you have race cars with custom dashes, aluminum interiors, wheel tubs and what I am finding out is they aren’t as much work as I thought -- but that said, getting them to actually fit and look good is a different story. Ahead of that story I will tell you we ordered a universal dash kit and wheel tub kit from Jegs. Our sheet metal working tools consist of a couple new tin snips, a straight-edge and a marker. It can be done. It turned out nice but “patience” is the key.

 

See you next month for Phase 4.  

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